March 9-10: Three Flags Day

Three Flags Day commemorates an 1804 event in St. Louis that finalized the 1803 Louisiana Purchase and thereby doubled the size of the United States. The Louisiana Purchase Treaty had been signed in in April of the previous year and ratified by the Senate on October 20. New Orleans had been transferred to the U.S.in December, but the ceremony transferring Upper Louisiana did not take place until March of 1804 in St. Louis. On March 9, the Spanish flag was lowered and the French flag was hoisted over the city. The next morning, the French flag was lowered and the U.S. flag was raised symbolizing the official transfer of the Louisiana Purchase to the United States. Explore these maps of the territorial expansion of the U.S. and other resources related to colonial French and Spanish history in North America.

March 9-10, 1804: Three Flags Day

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Meriwether Lewis

Meriwether Lewis (August 18, 1774–October 11, 1809) was an American explorer, soldier, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition. Portrait from the ClipArt ETC website.

Lewis & Clark Map

The route of Lewis and Clark through the Louisiana Territory to the Pacific Ocean. Map from the Maps ETC website.

US Expansion Maps

Over a hundred maps in this collection document the territorial growth of United States from the original 13 colonies to the Pacific Ocean.

Thomas Jefferson

Thomas Jefferson (April 13, 1743 – July 4, 1826) was the third President of the United States (1801–1809). He authorized the Louisiana Purchase. Portrait from the ClipArt ETC website.

Jefferson's Sate of the Union, 1803

President Jefferson used his annual message to Congress, October 17, 1803, to explain the reasons for moving forward with the Louisiana Purchase and the expected benefits regarding security and trade.

Jefferson's Sate of the Union, 1804

President Jefferson used his annual message to Congress, November 4, 1804, to review issues related to the Louisiana Purchase and the establishment of temporary government in the territory.

Flags for School Projects

If you are writing a report or making a presentation about anyplace in the world, the chances are that more than one flag has flown over the area in its history. You may just find the exact flags you are looking for in these collections of historic and contemporary flags.